Art op eormimxj images ajstd photograph produced thereby



SR la -$2,502

Feb. 5 1924.

A. AMES. JR

' ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY Original Fil d Jan. 12 1920 6 Sheets-Sheet 1 Feb. 5, 1924. 1,482,502 A. AMES, JR

ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY Original Filed Jan. 12. 19120 6 Sheets-Sheet 2 Feb. 5, 1924. 1,432,502 A. AMES. JR

ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY Original Filed Jan. 12, 1920 6 Sheets-Sheet 6 l2 \6 20 2f 26 32 36 #0 H- 45 5?. 56 60 6+ a ii) 2 "551 Feb. 5, 1924. 1,482,562 A. AMES. JR

ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY Original Filed Jan. 12. 1920 6 Sheets-Sheet 1 N O a O- I [,K O Q s i 0 e I I 1 i g 1 S I l I 1 x I I 1 I l I i I I I k I l 1 I x I I I Q l 1 g I I l t I l I K I 1 J 1 l l 1 I 1 I 1 1 i 1 I I l J l m 1 I o i U K a k I V- S 35 Mi 1 3 a 1 :4 *1: '1; x l

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A. AMES, JR

ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY 1920 6 Sheets-Sheet 5 lInI.l|- ill- I ML M P SQIHAWMM D u moo 7 +3 moo Original Filed hoe Feia. 5, 1924. 1,482,532 A. AMES. JR

ART OF FORMING IMAGES AND PHOTOGRAPH PRODUCED THEREBY Original Filed Jan. 12. 1920 6 Sheets-Sheet 6 1 ZJQMIL.

?ntented Feb. 5, 1924.

ADELIBERT ARIES, JR., OF HANOVER, NEW HAMPSHIRE Application filed January 12, 1920, Serial No. 351,011.

To all whom 2 0' may concern:

Be it known that I, ADELBERT AMES, Jr., a citizen of the United States, and resident of Hanover, in the county of Grafton and State of New Hampshire, have invented new and useful Improvements in the Art of Forming Images and Photograph Produced Thereby, of which the following is a specification.

This invention relates to a method or art of forming images for photographic and other uses, and to a photograph produced thereby.

Photography as heretofore carried out in a pictorial sense, has aimed to present to perception a record of the natural thing portrayed recognizable, with more or less aid by the imagination, as a reproduction of the object depicted.

At best, pictures formed by photography or otherwise are limited to a partial pre sentation only of the factors or qualities giving distinguishing appearance to natural Nat- I ural objects exist in tridimensional space objects as viewed by the human eye.

while a picture must be viewed as a plane projection, either thrown upon a screen, as a transparency seen against an illuminated background, or as an arrangement of light and dark places on a paper or other surface. at the object pictured is not and probably can not be reached by photographic or other means because of the artificiality of the pic ture due to these reasons. Absence of color is. of course, also a. factor in failure of illusion, but not the most important factor.

Apart from these inherent qualities of any picture, photography as heretofore practiced has also tailed of illusion in more subtle qualities. to the remedy of which the present invention is addressed. The makers.

of lenses have sought mathematically exact definition, absence. of distortion and correc tion of diffusion at all parts of the field rep resented by the photographic picture, so that the average photographic picture contains a too faithful record of the detailed outline and light and shadow in every portion of the whole angular field of view represented by the print or screen image constituting the picture.

Persons skilled in the graphic arts and competent critics of artistic eii'ort have long The complete illusion of looking;

Renewed August 3, 1923.

realized the illusive and esthetic limitations of pictures of this nature, of which the faults in general may be summed up as lack of concentration of attention at the center of interest, lack attainable illusion of depth, lack of illusion of the appearance of objects away from the center or" interest, lack of aerial or monocular perspective and lack of color (except in polychromatic photographs, in w)hich falsity of color is also characterist-ic With respect to color photographs as heretofore known faults of the same nature have been apparent to those skilled in the graphic arts; lack of concentration, lack of illusion of perspective, and particularly a general inaccuracy of edge and crudity of color value have characterized the best of such pictures.

These difiiculties in the prior art photographs [and in other pictures] may be broadly characterized as comprising typically a tendency to over-accurate definitiorn; resulting in essential falsity of the reproduction in respect to the image of the real object as perceived by the observer, and hence being disappointing to the eye expecting to find in the picture those aberrations natural 1 to the eye, and without which the reproduction must seem patently artificial, although the observer may be unable to analyze the source of the wrong appearance.

I have discovered by research, and shall hereinafter mention, certain relatively large distortions. diitusions and aberrations of the natural ocular appearances of nature which are absent from any photograph heretofore made, so far as I am aware, although I am aware of certain photographs deliberately made with lack of optical definition, or so treated as to be indefinite and fuzzy. Certain approximations of the distortions, ditt'usions and aberrations of the human eye have been attained in works of art by good painters. but even in this case they have been attained haphazard by the intuitive perceptions of graphic genius; the necessity and reason for imitating these appearances in the graphic arts has not been formulated. In the handiwork of painters the occasional simulation of these distortions. difi'usions and aberrations. therefore, has not been sys tematic or consciously reached, and has not been consistently and correctly attained with scientific accuracy. I am not aware that the nature, distribution and extent of the distortions, diifusions and aberrations proper to a photograph or other graphic representation have ever previously been determined, or ever proposed to be embodied in the picture.

Principal objects of the present invention are to provide an art or method of forming an image, and a photograph remilting from the practice of the art or method with the aid or" a camera and light-sensitive surfaces which shall give a subjective impression or illusion to the observer of the photograph similar to the impression given by the image received on the retina of the human eye in respect to the distortions, diffusions and aberrations of its various parts, whether the photograph is monochromatic or polychromatic. It will be understood that in the case of monochromatic photographs, the chromatic aberrations of the eye are also accounted for and translated into their monochromatic equivalents in order completely to obtain the character of illusion referred to in this specification.

I shall hereinafter find it necessary to describe some of the qualities of the images actually perceived of natural objects as an aid to description of making the new kind of image.

The bases of human visual imagery upon which the associative and artistic value of the pictorial arts are founded are the mental visual images which are stored up in the human mind. The nature of such images is based on the character and form of the images received on the retina of the normal human eye. The nature of these retinal images in turn is determined by our ordi nary habits of vision. In looking at a scene, we focus on some particular part of it due to its special interest or beauty. \Ve hold that focus a moment or two, and then look at another center of interest, or look away entirely. With each fixation of the eye a retinal image is formed which makes a mental impression of the same nature. Our mental visual images consist of a series of such impressions. To recall them mental impressions for associative or artistic reasons, a similar impression must be presented to our consciousness. This can be done only by presenting a picture with the characteristics of a retinal impression, i. e., having a center of focus well defined, and having all other parts more or less diffused to extents and in directions simulating the ocularappear-since of the object. When such a picture is looked at the fovea or clear-seeing part of the eye passes over it and recognizes its various parts with their characteristic diffusion and distortion as being similar to different parts of the mental visual image. It does this in the same way that the attendistortions, aberrations and ditfusions ap- I proximat-ing those characteristics of the sensory impression of the retinal image perceived by the normal eye, and includes a photograph resulting from practice of the method.

In the accompanying drawings,

Figure 1 is a diagram of the human eye illustrating certain of the aberrations of its lens system;

Figure 2 is a diagram illustrating one source of monocular perception of axial depth of field;

Figure 3 is a diagram in perspective illustrating tangential and radial astigmatic aberration;

Figure 4 is diagram illustrating another source of perception of depth of field;

Figure 5 is a diagram illustrating the tangential and radial astigmatic aberration of the eye;

Figure 6 is a diagram of the object field of the eye illustrating the loci of points having like astigmatic foci respectively for light of several colors;

Figure 7 is a diagram illustrating the geometric, linear or barrel distortion of the image of a rectangular object on the retina;

Figure 8 is a diagram illustrating the variable sensitivity of different regions of.

the retina to light of different colors;

Figure 9 is a diagram illustrating the dimensions of the chromatic circles of diffusion for different fixations of the eye and different colors;

Fig. 10 is a diagram of a photographic image according to this invention, and showing only those characteristics capable of such illustration.

In order to explain the characteristics of the method of forming images and the photographs resulting from said images herein described, comparison with the characteristics of the images formed by the human eye will aid understanding. The images herein referred to approximate the eye images in: I, the eifect in them of resolving power; II, the nature of the out-oft'ocus portions of the image; III, the quantity and distribution of the chromatic aber rations; IV, the radial and tangential ill astigmatic difi'usions; and V, in linear distortion.

I. The resolving power of the eye is limited not only by the aperture and the spherical and chromatic aberrations of the lens, as varied by the size of the pupillary opening, but also in eiiectis controlled by the sensory incapacity of the retina to perceive separate stimuli nearer together than the position of every second sensory cone. Separation of objects one minute of arc apart is the normal limit.

The eye is a smaller instrument than the usual practicable photographic apparatus, having an average focal length of 17 Photographic lens systems are seldom shorter than 59 in focal length, and characteristics of the new images are hereinafter explained upon a basis of a minimum focal length of 50 The high light-gathering or illuminating power of the eye need not be preserved in apparatus relied upon to practice the method at the cost of difiicult curvatures for glass or of inconveniently short-focus lens elements. The absolute size of diaphragm should preferably be kept the same as the pupillary opening. Pupillary openings vary normally from 2 to 6"; the ratio of aperture to focal length of the normal eye thus varies from 772.7 at low'illumination to f/8.5 in bright light; the lens system may havev a similar diaphragm and variable ratios of aperture to focal length between 778.3 and 772.5 with convenience. At maximum, the theoretical resolving power need not exceed that of the eye. The characteristic qualities of the new lens system are best attained in practice by lenses of relatively short focus.

II. Referring now to Fig. at, the image formed by the eye lens L on the nearly spherical retinal surface R, considering rays of any one color from objects nearly in the direct line of sight, at any fixation of focus will comprise a definite image a of a point in object A at the fixation distance. Every other object point D further away from the eye will have an image I! in front of the retina. and every point of object B nearer than A will have an image b behind the retina, and in either case the out-offocus light on the retina will be represented by a circle 0'. a wider than the image a. The size of these circles depends on the ration of pupillary aperture to focal length,

and their perception is important to monocular perception of distance. These out of-focus point images are circular only when in the line of sight.

The image a of point A is not, however. a point. The eye lens. approximately of spherical surfaces in the normal eye. has the spherical aberration of all such simple lenses, so that some of the light from B is focused in front and some behind the retina, the best focus being a concentrated part. of the bundle. lVe may, however, disregard spherical aberration so long as it is within the resolving power capable of separating objects about 1 minute of arc apart.

III. Chromatic aberration is more important. Referring to Fig. l. a perfect image of a white light at a can not exist on the retina simultaneously of all of the components of that light. If fixation is upon the brightest component of the white light, in the yellow part of the spectrum, the red light will be focused at 1" and the blue light at b. The image will thus consist of a clearly defined yellow point a, a circle 1 1*, of blue and red light out of focus, and an overlap-ping ring 5 6 of the more refrangible blue. Since diffusion is at the cost of intrinsic brightness, the purple and blue halo about the bright point a will be more salient when the background is dark.

Referring now to Fig. 2, the bright image on the retinal surface R of the point A whatever the color of the light emanating from A will have a characteristic chromatic halo Z), 5 whereas the bright image of a nearer point B will have a differznt characteristic chromatic halo 6*, 6*. It will be observed from this fact that the chromatic aberration of the eye aids in the monocular sense of distance; since the eye perceives the characteristic chromatic aberration peculiar to the distance of the object whose image hears it, and relies on the appearance for the perceptive estimate of the distance.

It need not be explained that the peculiarities of chromatic aberration follow the images of objects placed out of the line of sight or optical axis of the eye; the color distribution of the halo or fringes surrounding bright points may be shown in a manner similar to that mentioned above to definitely establish the distance of the object in its relation to the eye. lVe therefore expect to see a certain color fringe or halo characteristically placed with respect to the objects in and away from the line of sight depending in amount and form upon their distance, their departure from the axis of the eye, and upon the accommodation of the eye.

IV. Considering again the case of monochromatic vision, the nature of the image in the human eye is modified by radial'and tangential astigmatism. Referring to Figs. 3 and '7, let us suppose the .line 1-1 to be' th optical axis, and the line 2-2 to be the central ray through the center of the lens from the point B displaced from the axis l-l by a substantial angle.

All of the light from the point B will pass through no single point in the line 2. The oblique passage of the bundle of rays through the lens L results in the concentration of the image in two regions, the first in a substantially tangential line with respect to the axis 1, and the second in a substantially radial line with respect to the axis 1. The mean between these regions of first astigmatic focus and second astigmatic focus is a region of least astigmatic confusion, atwhich the bundle of rays is substantially circular, but not a true image of the point B. As illustrated in Fig. 3, the first or tangential astigmatic focus is shown at w, m, the second or radial astigmatic focus is shown at y, 1 and the circle of least confusion at The optical conditions in the eye are such that the retinal surface R throughout its greater portions occupies a position between the first and second astigmat-ic foci f, f of equidistant objects.

For every fixation of the eye with respect to a definite objectin the field of view some difi'erent part of the astigmatically illuminated image region m, w, y, 1 Fig. 3. of the object will be projected upon the retina, and there will be differentdifi'usion of edge or point depending upon whether this intersection of the retina with the astigmatic region is nearer the tangential focus m, w, or near the radial focus 1 1 Referring to Fig. 5, let us assume the case of an object in the direction of the point B and an object a lying in the direction of a point A and at a lesser angle to the axis 1, 1. Points exist on the lines L, A, and on the lines L, B, wherein the obects b and a respectively produce upon the retina a tangential astigmatic focus, and other places exist along these same lines L, A, and L, B, at which other objects produce upon the retina radial astigmatic tool.

For every fixation of the eye at a given focus then, there will exist two regions in the object field in which every source of light is imaged as a tangentially astigmatic or a radially astigmatic image, respectively, objects between these spaces in the object field being projected upon the retina in ellipsoidal forms having their greatest elongation tangentially or radially arranged as the image of the object is nearer to the tangential or radial astigmat-ic focus.

For any given fixation ot the eye, focus of the tangential astigmatic image on the retina is possible for light of one color proceeding from any object occupying any place in a certain fixed surface in space.

Focus on the retina of the radial astigmatic images corresponds to another locus in space of objects capable in that fixation of the eye of forming such images.

For every dilterent color of light, the positions of the objects forming astigmatic foci respectively tangential and radial will be different. For any fixation of the eye. then, we may discover in space a particular surface upon which all objects will form their respective astigmatic images in a particular color. This will be plain from 8, which plots the locus of these object surfaces for a normal eye fixed at two meters focus respectively for the radial and the tangential astigmatic foci of typical red, yellow, green and blue wave-lengths.

I attribute a greater part of the monocular perception of distance of objects oil the axis to the perception of the direction and extent of the astigmatic diffusion resulting from the optical considerations mentioned above.

V. The optical mechanics of the eye also produce a well-understood optical and a larger geometrical distortion of the image now referred to with the aid of the explanatory diagram in Fig. 7. The retina is a segment of a sphere, with respect to which the eye lens is not central, and the projection of vertical and horizontal lines upon this surface at angles from the central axis are curved intercepts of planes with this sphere. Comparing the image on the retina with the natural appearance, the rectangular grid having verticals l0 and longitudinals 11. Fig. 7, produces an image having a vertical curve 12 and a horizontal curve 13, respectively.

The clear-seeing region [tovea centralis] is of the order of one degree of angular magnitude only, and is surrounded by the yellow spot. so-called, extending about six degrees on the horizontal median line and about four degrees on the vertical meridian of the eye. The sensitivity of the retina outside of these regions has marked peculiarities; we therefore have to deal, when considering the appearance of natural 01 jects as really perceived, not only with the optical distortions due to the lens system of the eye but with the perceptory peculiarities due to the mechanism stimulated by the optical image. I

The sensitivity of the different regions of the retinal surface to differences of color is different. Referring to Fig. 8, the ordinates of the diagram indicate wave lengths of light and the abscissa) percentages of sensitivity of the difierent regions for the normal eye. The tovea centralis is most sensitive to the region of spectrum lying i1nmediately below the bright yellow ID line. The sensitivity of the yellow spot is slightly greater for short wave lengths: and the sensitivity of the region within lO from the optical center is less acute for bright yellows. reds and greens and more acute for blues and violets. The trace marked Low illumination illustrates the distributions with respect to color of the maxima and minima of perception when under low illumination.

The quantitative size of some of the aberrations and diflusions mentioned above will be plain from the diagram Fig. 9, which plots for a fixation at a distance of two meters, the angular size in radians of the circles of diffusion for light of different colors emanating from points placed at the respective distances indicated by the scale of ordinates. The apparent size of such circles of diffusion for any color at the distances shown is a. product of its angular diameter in radians shown on the scale at the left by its distance from the eye. These quantities are relatively large.

In order to produce pictures having the characteristics of a retinal image the aberrations, difiusions and distortions mentioned above must not only be present in the picture but they must be present in the proper relative amounts. For instance, pupillary opening, focal length, chromatic aberration, astigmatism, and retinal sensitivity each contributes to the nature or" colored edges; proper portrayal of these edges can be arrived at only by providing these characteristics in the same proportions and directions.

I regard it as particularly important that the lens system used in the practice of the method produce tangential and radial astigmatic images related to the sensitive plate in substantially the same manner and to substantially the same degree as those of the eye are related to the retina.

I do not hereimclaim and need not further particularly describe in detail a lens system adapted to produce images of the character sufliciently indicated above, such a lens and lens system being the subject of a divisional application according to the requirement of the Patent Office and filed June 2, 1921, Serial No. 474,561.

It will be understood without further description that a suitable lens system, for example, such as shown in my said application will refractively cause the diffusions, aberrations and distortions mentioned above as a consequence of refraining from introducing any of the ordinary corrections for these aberrations, diffusions and distortions and as a further consequence of forming the respective surfaces and controlling the respective distances and thicknesses of the elements, dependent upon their index of refraction, to secure the astigmatic and other aberrations and distortions as mentioned in detail above, and that the precise curvatures of the respective elements or" the lens are a function of the selected focal length, of the selected range of diaphragm opening, and of the selected lowdispersion and high-dispersion glasses at the command of the optical workman.

Photographs produced by the exposure of a sensitive plate in the image-plane of an image-former having the described characteristics portray the object-field with the characteristic difi'usions due to the optical aberrations and distortions above explained, and therefore have the characteristic property of correct monocular illusion of depth, as Well as of concentration at the center of interest or such parts of the picture as are to be seen in acute definition. Such photographs are a characteristic product, also herein claimed, of the new method or art.

Referring to Fig. 10, which is a diagram of the photograph of an arbitrary supposititious series of like objects in an object-field, let it be supposed that the cross m is in focus, at the fixation point of the imageformer and on its axis. This object is well donned, and its edges against the general background will have a minimum chromatic halo and a minimum diffusion due to astigmatism.

The similar crosses m in the distance and off the axis will not have the same appearance as the cross m. Aside from their lesser angular magnitude, edges lying in the radial directions R, R, or principally in these directions, will be relatively well defined, except for the chromatic aberration explained above in connection with Figs. 2 and 6. Edges lying in the generally tangential directions T, T, will be strongly diffused, owing to the astigmatic diffusion appropriate to their angles from the axis and their distance in the line of sight, as explained in connection with Figs. 3 and 6 above. The relative color of these difi'used edges will also be characteristic of the position of these objects, as explained above.

The similar crosses m in the foreground will have a still diflerent appearance. The principal astigmatic diffusions will be of edges along the radial directions R, R, the tangential edges in directions T, T being better defined, but all of the edges will again have difi'usions of a color characteristic of the position of the objects. These diti'usions are all substantially of the degree of the corresponding ocular diifusions.

Let it be supposed that the object-field contains an object Q having lines or edges g, g which in rectilinear geometric projection would be straight. These edges will appear in the photograph not only with the difi'usions explained in connection with the objects m, m, m, but will be geometrically distorted according to the relation explained above in connection with Fig. 7.

In each instance of diffusion or distortion, the photograph contains on appearance appropriate to the three-dimensional position of the object and the position of the attenltion-point, and affirmative to the perception of the observer of these facts of the object. The illusion of reality thus obtained can only be approximated accidentally, and then only for objects of fortuitous position, by images which are either well-focussed throughout, rectilinear, or corrected in general; or

which are out of focus, blurred, or focussed as to one arbitrary plane of the object-field, and miscellaneously aberrated elsewhere.

I claim 1. A photographic picture characterized by definition corresponding to the monocular perception of axial depth of the normal human eye at the center of interest, and by diffusion due to substantial optical aberrations of the image at other parts of the picture.

2. A photographic picture characterized by definition corresponding to the monocular perception of axial depth of the nor mal human eye at the center of interest, and by diffusion due to increased chromatic aberrations of the image at other parts of the picture.

3. A photographic picture of an objectfield having therein an axial center of interest in which the definition of objects along the axis is subject to diffusion according to their displacement in the line of sight, and having therein at regions angularly displaced from the center of interest depictions of objects subject to ditiusions substantially corresponding to the optical aberrations of the like images perceived by the human eye.

t. A photographic picture of an objectfield having therein an axial center of interest in whiclrthe definition of objects along the axis is subject to diffusion according to their displacement in the line of sight, and having therein at regions angularly displaced from the center of interest depictions of objects subject to diffusions and rectilinear distortions substantially corresponding to the optical aberrations of the like images perceived by the human eye.

5. A photographic picture of an objectfield having therein depictions of objects in the axial line of sight subject to diffusion by chromatic aberration and by variation of focal distance, but otherwise sharply defined, and also having therein depictions of objects at all other parts of the object-field characterized by radial and tangential astigmatic diffusion according to the angular displacement, distance and color of the respective objects, said diffusions being of the kind and substantially of the degree characteristic of the retinal image in the normal human eye.

6. A photograph comprising a depiction of an object-field substantially corresponding as regards diffusion of detail, points and edges of objects depicted to the instantaneous retinal image of the same object-field as perceived by a normal human eye.

7. The art of forming images giving a subjective impression similar to the ocular impression of natural objects com rising producing by refraction an image iaving tially the illusion of axial depth and chm-7 matic aberration characteristic of the ocular image in the normal human eye.

9. The art of photography comprising as a step, for the improvement of the illusion of an ocular impression of natural objects, forming and recording an optical image of the object-field photographed with the aid of refractive devices producing substantially the astigmatic aberration characteristic of the ocular image in the normal human eye.

10. The art of photography comprising as a step, for the improvement of the illusion of an ocular impression of natural objects, forming and recording an optical image of the object-field photographed with the aid of refractive devices producing substantially the chromatic aberration, astigmatic aberration and distort-ion characteristic of the ocular image in the normal human eye.

11. The art of forming images for photography by the refraction of light from the object by a plurality of glass lenses of appropriate predetermined form and appropriate densities through an aperture, comprising as a step the inexact focusing of the image upon parts of a fiat image surface, the image being characterized by dilferent astigmatic aberration at the image surface in radial and tangential directions of light from objects dili'erently placed in the object field, the direction and nature of the said difiusions being substantially those characteristic of the ocular image of the normal human eye.

12. The art of forming images for photography by the refraction of light from the object by a plurality of glass lenses of appropriate predetermined form and appropriate densities through an aperture, com prising as a step the inexact focusing of the image upon parts of a flat image surface, the image being characterized by different astigmatic aberration at the image surface in radial and tangential directions of light from objects differently placed in the object field, and by linear distortion, the direction and nature of the said diffusions and distortion being substantially those characteristic of the ocular image of the normal human eye.

Signed by me at Boston, Massachusetts, this thirtieth day of December, 1919.

ADELBERT AMES, J R. 

